From 3e1396f8cfa61e115d36c7cb42255d20b6fc1f41 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Fri, 13 Dec 2019 14:56:16 -0800 Subject: [PATCH] Input: add safety guards to input_set_keycode() commit cb222aed03d798fc074be55e59d9a112338ee784 upstream. If we happen to have a garbage in input device's keycode table with values too big we'll end up doing clear_bit() with offset way outside of our bitmaps, damaGing other objects within an input device or even outside of it. Let's add sanity checks to the returned old keycodes. Mot-CRs-fixed: (CR) CVE-Fixed: CVE-2019-20636 Bug: 153715664 Reported-by: syzbot+c769968809f9359b07aa@syzkaller.appspotmail.com Reported-by: syzbot+76f3a30e88d256644c78@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20191207212757.GA245964@dtor-ws Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman Signed-off-by: Jignesh Patel Change-Id: I819da9e84f4e91140514e22fd6d4afc43359a3d2 Reviewed-on: https://gerrit.mot.com/1604271 SLTApproved: Slta Waiver SME-Granted: SME Approvals Granted Tested-by: Jira Key Reviewed-by: Xiangpo Zhao Submit-Approved: Jira Key (cherry picked from commit a5aaf589dabb64175e48d82cbcf624cdb0564934) --- drivers/input/input.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/input/input.c b/drivers/input/input.c index 50d425fe6706..cadb368be8ef 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -858,16 +858,18 @@ static int input_default_setkeycode(struct input_dev *dev, } } - __clear_bit(*old_keycode, dev->keybit); - __set_bit(ke->keycode, dev->keybit); - - for (i = 0; i < dev->keycodemax; i++) { - if (input_fetch_keycode(dev, i) == *old_keycode) { - __set_bit(*old_keycode, dev->keybit); - break; /* Setting the bit twice is useless, so break */ + if (*old_keycode <= KEY_MAX) { + __clear_bit(*old_keycode, dev->keybit); + for (i = 0; i < dev->keycodemax; i++) { + if (input_fetch_keycode(dev, i) == *old_keycode) { + __set_bit(*old_keycode, dev->keybit); + /* Setting the bit twice is useless, so break */ + break; + } } } + __set_bit(ke->keycode, dev->keybit); return 0; } @@ -923,9 +925,13 @@ int input_set_keycode(struct input_dev *dev, * Simulate keyup event if keycode is not present * in the keymap anymore */ - if (test_bit(EV_KEY, dev->evbit) && - !is_event_supported(old_keycode, dev->keybit, KEY_MAX) && - __test_and_clear_bit(old_keycode, dev->key)) { + if (old_keycode > KEY_MAX) { + dev_warn(dev->dev.parent ?: &dev->dev, + "%s: got too big old keycode %#x\n", + __func__, old_keycode); + } else if (test_bit(EV_KEY, dev->evbit) && + !is_event_supported(old_keycode, dev->keybit, KEY_MAX) && + __test_and_clear_bit(old_keycode, dev->key)) { struct input_value vals[] = { { EV_KEY, old_keycode, 0 }, input_value_sync -- 2.20.1